Method and apparatus for photometric analysis of sample fluids for a constituent of interest. There is provided a method of sample analysis comprising the steps of locating the sample fluid in a cell having an axis, directing a ray of light through the sample and the sample-cell interface at an angle to said axis, totally internally reflecting said light ray passed through the interface to be redirected across said sample, and detecting the redirected light ray passed through the sample.
The present invention features a system for detecting a substance in a fluid sample. A capillary is provided with a longitudinal axis and a channel is formed in it for receiving a fluid sample. The channel is disposed parallel to the longitudinal axis. A reflecting surface surrounds the outer surface of the capillary for reflecting electromagnetic energy. The reflecting surface has an incident window for allowing the electromagnetic energy to enter the capillary and an exit window for allowing the electromagnetic energy to exit the capillary. The exit window is disposed downstream of the incident window with respect to the longitudinal axis, so that the electromagnetic energy that enters the capillary is internally reflected more than once by the reflecting surface.
A spectroscopic detector cell which is particularly suited to the analysis of low flowrate and small volume liquid samples in micro-flow injection analysis or titration and microbore, high pressure liquid chromatography, wherein interference from bubbles in the flow path of the light passing through the cell is substantially eliminated by using a serpentine coil of small-bore, transparent(to the light employed for a given analysis), overlapping tubing for carrying the liquid to be analyzed at a high enough velocity to sweep away any otherwise interfering bubbles that might be formed in the liquid, and by immersing the coil in a second fluid (a gas or a liquid) which possesses the same refractive index as the tubing material and which also is transparent to the light employed for a given analysis.
A particle counter operates by the opacity method and has a light barrier or electric eye. The light beam of the light barrier or electric eye penetrates a measuring channel for a fluid transverse to the passage of the fluid through the channel. An electronic analysis assembly is connected in series following the receiver of the light barrier or electric eye. The light emitting surface of the light barrier or electric eye is formed by the end surface of a light-emitting fiber. The light inlet or receiving surface is formed by the end surface of a receiving fiber. The end surface of light-emitting fiber lies in a first boundary surface of the measuring channel. The end surface of the receiving fiber is concentric to the light-emitting fiber end surface and is located in a second boundary surface of the measuring channel parallel to the first boundary surface.
A liquid sample analyzer comprises an open, sample determining channel in the form of a small gap, means for supplying liquid sample to the channel, means for injecting a fluid into the channel to rinse its interior, and means for determining the optical density or the ion concentration of the liquid sample supplied to the channel. In this manner, the concentration of liquid sample such as blood is automatically determined and analyzed.
A device for detecting a conduit and for determining at least one characteristic of its content includes a seat for housing at least a portion of the conduit. The seat has first and second zones which are opposite each other with respect to a recess intended to receive the conduit. A light emitter is arranged in the first zone, and has a preferential emission direction oriented towards the recess. A receptor sensitive to the light emitted by the emitter also has a preferential reception direction oriented towards the recess. A first deflector deflects light in the direction of the first zone when a conduit containing a substantially transparent liquid is engaged in the seat. A second deflector deflects in the direction of the second zone at least part of the light deflected by the first deflector so that, when a conduit containing a substantially transparent liquid is engaged in the seat, at least part of the light emitted by the emitter reaches the receptor after having passed through the conduit at least twice obliquely with respect to a longitudinal axis of the recess. The components are arranged so that in the absence of a conduit in the seat, at least part of light from the emitter reaches the receptor after a single deflection.
